The present invention relates to a heater apparatus for heating the passenger compartment of a motor vehicle.
The passenger compartment or cabin of a motor vehicle is generally heated by a heat source employing the cooling water of the internal combustion engine on the motor vehicle. However, in cold weather, it takes time to increase the temperature of the cooling water, and hence the compartment cannot be heated quickly.
Japanese Laid-Open Patent Publication No. 61-157422 discloses a proposed vehicle heater device in which fuel is combusted by a burner separate from the internal combustion engine and heat generated by the fuel combustion is recovered by a heat exchanger to supply heating air into the compartment.
In the event that a heating blower is turned off by stopping the operation of the vehicle, turning off a main power supply, or for some other reasons while the heater device is in operation, the fuel combustion in the burner is ceased, but the temperature of the heat exchanger and other components is not quickly lowered because of a heat buildup around the combustion chamber of the burner. The instant the blower is stopped, the temperature may rather be increased into a dangerous range.